PSA Doubling Time (PSADT)
Time for PSA to double. Key prognostic factor after biochemical recurrence. Shorter PSADT suggests more aggressive disease.
Did our AI summary help? Let us know.
<3 mo: high risk 3-12 mo: intermediate >12 mo: lower risk
Ready to run the numbers?
Why: PSADT guides salvage radiation, ADT timing, and imaging. <3 months: high risk; >12 months: lower risk.
How: PSADT = ln(2) / slope of ln(PSA) vs time. Linear regression on 2+ PSA values.
Run the calculator when you are ready.
Slow PSA Doubling
Biochemical recurrence with favorable kinetics
Click to load
Rapid PSA Doubling
Aggressive recurrence requiring intervention
Click to load
Stable PSA
Minimal change over time - likely benign
Click to load
Post-Radiation PSA Rise
Biochemical failure after external beam RT
Click to load
Active Surveillance
Monitoring low-risk prostate cancer
Click to load
PSA Measurements
Enter at least 2 PSA values with their timing. Most recent measurement should have 0 months ago.
Clinical Context (Optional)
For informational purposes only — not medical advice. Consult a healthcare professional before acting on results.
🏥 Health Facts
Key prognostic factor post-recurrence
— AUA
Requires 2+ PSA values
— Guidelines
📋 Key Takeaways
- • PSADT = ln(2) / slope from linear regression of ln(PSA) vs time
- • PSADT <3 months: 20-fold higher cancer mortality—immediate systemic therapy
- • Use at least 3 PSA values spanning 6+ months for reliable calculation
- • Post-surgery vs post-radiation kinetics differ; PSA bounce after brachytherapy is benign
- • PSADT guides salvage radiation timing, ADT decisions, and imaging frequency
💡 Did You Know?
❓ Frequently Asked Questions
How many PSA values do I need for PSADT?
Minimum 2, but 3 or more spanning at least 6 months provides more reliable calculation. More points improve accuracy and R² value.
What if my PSA fluctuates?
Check R² value—if low, calculation may not be reliable. Consider more measurements or lab variation. PSA velocity is an alternative metric.
Is PSADT different after surgery vs radiation?
Yes. Post-surgery, any detectable PSA indicates recurrence. Post-radiation, nadir and bounce phenomena complicate interpretation.
When should I start ADT based on PSADT?
PSADT <10 months generally favors earlier treatment; >15 months may allow observation. Consider symptoms, imaging, and patient preference.
📊 PSADT by the Numbers
📚 Official Data Sources
⚠️ Disclaimer: This calculator is for educational purposes only. Prostate cancer management decisions should be made with a urologist or oncologist. PSADT is one factor in comprehensive assessment.
Related Calculators
PSA Density Calculator
Calculate prostate-specific antigen density to assess prostate cancer risk and guide biopsy decisions.
healthBladder Volume Calculator
Calculate bladder volume from ultrasound measurements using the prolate ellipsoid formula for post-void residual (PVR) and bladder capacity assessment.
healthAlbumin-Creatinine Ratio (ACR) Calculator
Calculate urine albumin-to-creatinine ratio for kidney disease screening and monitoring per KDIGO guidelines. Includes classification into A1, A2, and A3...
healthAdrenal Washout Calculator
Calculate CT washout percentages to differentiate adrenal adenomas from malignant lesions using absolute and relative washout formulas based on Hounsfield...
healthBUN/Creatinine Ratio Calculator
Calculate the BUN to Creatinine ratio to differentiate prerenal from intrinsic renal causes of kidney dysfunction. Includes interpretation for prerenal...
healthCreatinine Clearance Calculator (Cockcroft-Gault)
Calculate creatinine clearance using the Cockcroft-Gault equation for drug dosing and kidney function assessment.
health